The iNCOVACC, India's first Covid vaccine in the form of a nasal spray, by Bharat Biotech, got its approval from the DGCI for emergency use authorisation and is now available on the CoWIN app. It can also be used as a booster for adults. As the SARS-CoV-2 first infects the body in the nasal pathways and creates a protective coat of antibodies, it is this very site that the nasal spray targets. The dose has been developed by the Washington University School of Medicine.
According to the government's official press release, BBV154 is an intranasal replication-deficient chimpanzee adenovirus SARS-CoV-2 vectored vaccine. It consists of a replication deficient ChAd vector expressing the stabilised Spike SARS-CoV-2 (Wuhan variant). Dr Rajesh S. Gokhale, Secretary, DBT (Department of Biotechnology), and Chairperson, BIRAC (Biotechnology Industry Research Assistance Council) speaking on the subject said, “The department through 'Mission Covid Suraksha', is committed to the development of safe and efficacious Covid-19 vaccines. BBV154 Covid Vaccine is the first intranasal vaccine approved by DCGI for primary immunization against Covid-19 in the 18+ age group for restricted use in emergency situation being developed in the country under 'Mission Covid Suraksha' and adds to our repertoire of Covid-19 vaccine. This is an excellent example of Aatmanirbharta initiative of the government of India."
In a research paper published on March 8, 2022, in the Human vaccines and Immunotherapeutics journal, Kuldeep Dhama from the Indian Veterinary Research Institute in Bareilly, says while intramuscular (IM) injections elicit protective cellular immunity, the intranasal (IN) vaccines induce a significant amount of antibody-mediated immune response, a robust cell-mediated immunity and also stimulate protective mucosal immunity. "By inducing secretory IgA antibody responses specifically in the nasal compartment, the intranasal SARS-CoV-2 vaccine can prevent virus infection, replication, shedding, and disease development, as well as possibly limit virus transmission," said Dhama in his paper which threw a light on the prospects, and challenges in developing intranasal Covid-19 vaccines for countering the ongoing pandemic.
"IM injected vaccines are primarily intended to generate both antibody-mediated and T cell-mediated immune responses. Still, it has been found that these vaccines are inefficient in stimulating IgA secretion in mucosal cells, which may not be efficient in controlling the influx of viral particles in the upper respiratory tract. Preclinical results in numerous animal models have demonstrated the promising potential of intranasal Covid-19 vaccination. A range of IN vaccines has been generated by clinical investigations in mouse models and rhesus macaques, which have demonstrated activation of the mucosal immunity (sIgA) in both the upper and lower respiratory tracts along with a significant degree of humoral and cell-mediated immune responses that can inhibit viral reproduction and transmission/spread. The intranasal vaccine is an exciting method for preventing Covid-19 since the nasal mucosa provides the first-line barrier to SARS-CoV-2 entrance before dissemination into the lungs. Hence, developing effective and reliable intranasal vaccines is crucial at this time," he said.
The government has made it clear that the approval given currently is for this vaccine to be used only as a precautionary dose in those above 18. Those who have already taken one need not avail of this. It is now available through the CoWin platform, must be stored at a temperature between two to eight degrees Celsius, which is the normal refrigerator temperature, and has to be used once opened and out of the refrigerator within six hours. "However, as of now we still don’t know the efficacy of this vaccine. There are other boosters already available, but given that the nasal spray straight away targets the upper respiratory tract, I think this is a good alternative,” said Dr Anand, pulmonologist from Manipal.